Ammunition feed mechanism



G. P. S. CROSS AMMUNITION FEED March 14, 1961 MECHANISM 3 Sheets-Sheet 1 Filed Sept. 2, 1947 [nvenfor March 14, 1961 G. P. s. CROSS AMMUNITION FEED MECHANISM 3 Sheets-Sheet 2 Filed Sept. 2, 1947 r62 2 P S Gross IIIIIIIIIIIIII 1| March 14, 1961 G. P. s. CROSS AMMUNITION FEED MECHANISM I5 Sheets-Sheet 3 Filed Sept. 2, 1947 1120912101" Garrett P5. C r0515 Patented Mar. 14, 1961 UNITION FEED MECHANISM Garrett P. E5. Cross, Beverly, Mass, assignor to United Shoe Machinery Corporation, Flemington, N.J., a corporation of New Jersey Filed Sept. 2, 1947, Ser. No. 771,677

1 Claim. (CI. 89-33) The invention relates to an automatic ammunition feed mechanism of the type used on aircraft guns, the feed mechanism being supplied with cartridges from a linked belt.

It is an object of the present invention to provide an ammunition feed mechanism of this type with improved means for horizontally feeding the belt to the gun, i.e., int position above the mouth of the feed mechanism from where successive cartridges are stripped from the belt and moved down into position in the path of the breech bolt of the gun.

In accordance with a feature of the invention, a reciprocating horizontal feed member or pusher is moved into position to feed the belt by means energized by the recoil of the gun, and a link support which facilitates the stripping operation is so controlled by the belt feed member that it does not interfere with the feed movement of the belt.

This and other features of the invention will be apparent from the following detailed description and will be pointed out in the claim.

In the drawings,

Fig. 1 is an angular top view of the feed mechanism, the cover of which has been removed;

Fig. 2 is a vertical sectional view of the feed mechanism;

Fig. 3 is a section on the line lII-III of Fig. 2;

Fig. 4 is a section on the line IV-IV of Fig. 2;

Fig. 5 is a section on the line V--V of Fig. 2; and

Fig. 6 is a detail view of a link support for facilitating stripping of the cartridges from their belt.

The invention is shown as embodied in a feed mechanism for providing a 20 mm. aircraft gun with ammuniticn and is particularly concerned with the horizontal feed unit of a feed mechanism of the type disclosed in an application for United States Letters Patent filed in the name of Charles K. Woodman under Serial No. 674,542 on June 5, 1946.

The feed mechanism is contained in a housing 10 (Figs. 1 and 2) adapted to be mounted on a gun G a portion of which is shown in Fig. 3. The horizontal feed unit of the mechanism brings successive cartridges, which are supplied to the feed mechanism by means of a belt, through a chute 12 formed in a cover 14 which is detachably secured to the housing 10 and moves the cartridges into a position above a mouth 16 of the feed mechanism. The cartridges, successively moved into position above the feeder mouth, are stripped from the belt, and moved downward into position to be picked up by the breech bolt of the gun, by stripper and vertical feed mechanisms (not shown) which are fully described in the aforementioned application.

A horizontal feed movement is imparted to the cartridges by a feed member or pusher 18 (Fig. 1) which has cars 19 rotatably mounted on a pin 20 (Fig. 3). The pin 20 at its outer ends carries rolls 22 (Fig. 1) which move in hor'zontal guideways 24 in the housing 10.

Projections on the pusher are normally held in an upwardly inclined position (see Fig. 3), to engage the rear faces of successive cartridges, by means of a plunger 26 seated in a housing 28 formed on a link 30, a spring 32 normally urging the plunger into engagement with a face on the pusher 18. The extent of upward movement of the pusher 18 about the axis of the pin 20 is limited by engagement of the left ear 19 (Fig. l) with the top of the plunger housing 28.

The link 30 is also mounted on the pin 20 and is pivotally connected to a double-armed feed lever 34. The lever 34 is mounted to oscillate about a shaft 36 (Fig. 2) and serves to impart feed movementsto the pusher 18. The shaft 36 is rotatably mounted in bearings of the housing 10 and extends through a cylindrical extension of the housing.

The energy or force for imparting feed movement to the pusher 18 is derived from a torsion spring 38 which is energized by the recoil movement of the gun. The spring 38 surrounds a spacer 40 on the shaft 36. One end of the spring is secured to a hub of the feed lever 34 and the other end of the spring is joined to an anchor 42. The anchor 42 is rotatably mounted on the right hand end (Fig. 2) of the shaft 36 and extends partially within a sleeve 44 forming the end of the cylindrical extension of the housing it Longitudinal movement of the anchor 42 relatively to the shaft 36 is prevented by a retaining member 46 (Fig. 4) which is pivoted to the anchor 4-2 and is moved into engagement with an annular groove in the shaft by a spring 48. The anchor 42 is normally held locked against rotary movement by a non-rotary toothed ring 50 (Fig. 2) engaging a ratchet 52 integral with the anchor 42. The ring 50 is mounted within the sleeve 44 and is movable longitudinally thereof along the inner face of the sleeve. A spring 54 tends normally to hold the ring 50 in locking engagement with the ratchet 52 and to hold the spring 38 under preliminary tension. The tension of said spring 38 may be varied by rotation of the anchor 42.

The spring 38 is energized and the pusher 18 is retracted from the feeder mouth from the position it assumes at the end of its feed movement into the position it assumes at the beginning of its feed movement by a cam lever 56 (Figs. 1, 2, and 3) secured to the shaft 36 between the arms of the feed lever 34. Pivoted to the bifurcated upper end of the lever 56 is a hook 58 which is yieldingly held in engagement with a pin 60 on the lever 34 by a springpressed plunger 62 (Fig. 3). At its inner side the lever 56 carries a cam roll 64 engaged by a cam 66. The cam 66 is mounted on an arm 68 secured to a shaft 70. The shaft 70 is carried by a rear bracket 72 and a forward bracket (not shown) attached to the breech casing of the gun G, the casing reciprocating with the moving gun parts.

The lever 56 is actuated by the cam 65 upon movement of the gun in recoil to swing outward, i.e., in a clockwise direction (Fig. 3) swinging the lever 34 correspondingly about the axis of the shaft 36 to move the pusher 18 outward into position to assume feed control over another cartridge. This clockwise movement of the lever 34 serves simultaneously to energize the spring 33. The feed lever 34 is swung in a clockwise direction until a projection 74 on the hook 58 engages a release plate 76. The plate 76 is pivotally joined to the housing 10 by a pin 78 and is held in operative position by a spring 80 mounted on the pin. Engagement of the projection 74 with the plate swings the hook 58 out of engagement with the pin 60, whereupon the released feed lever 34 is swung in the opposite direction by the spring 38 imparting a feed movement to the pusher 18 through the link 30. The plate 76 may be swung into an inoperative position about its pivot 78 to permit certain adjustments of the operating parts to be made. The swinging movement of the lever 34 in a counterclockwise direction is terminated by the engagement of a face on the lower side of said lever with a yielding plate 81, mounted in the housing and supported by buffer springs. At the end of the counter-recoil movement of the gun, the cam 66 releases the cam roll 64 and the hook 58 is returned to locking engagement with the pin 60, to recouple the levers 34, 56, by its spring-pressed plunger 62 and by a spring 82 (Fig. 3). The spring 82 engages a projection 84 on the cam lever 56 and surrounds a vertical pin 86 secured in the housing and extending through an opening in the projection 84.

Movement of the cartridges, i.e., the belt, away from the feeder mouth in a direction opposite to the direction of feed is prevented by detents 88 (Fig. 1). The detents 88, as shown in Fig. 5, are pivoted within the housing 1t and extend through openings in the housing into the tridge is in its position above the feeder mouth 16, a'

link support 92 (Fig. 3) is provided which engages the link portion between the leading and the following cartridge. The link support 92 is mounted below the pusher 18 and the link 30 and has a longitudinal slot 94 through which extends a fulcrum pin 96 secured in the housing 10. The fulcrum pin 96 permits longitudinal movements of the link support 92 as well as swinging movements about its axis. A spring 98 engaging a pin 100 on the inner end of the link support 92 normally swings the link support 92 downward about the axis of the pin 96 and holds it in its operative position in engagement with the top of the right-hand wall forming one side of the feeder mouth 16.

A projection 102 on the pusher 18 engages in a longitudinal slot (not shown) in the link support 92. When the pusher 18 is moved away from the feeder mouth, the projection 102 first moves idly in the slot of the link support 92. Upon'engaging the end of the slot, however, the pusher carries the link support with it away from the feeder mouth. It is also important that the link engaging end of the support 92 shall not interfere with the'feed movement of the next cartridge. Therefore, in moving away from the feeder mouth, the link support is simultaneously swung downward about the axis of the pin 96 by the spring 98, along the face of a cam 1114 secured within the housing 10 adjacent to the right hand Wall of the feeder mouth 16. During the feed movement of the pusher, the projection 102 again first moves idly in the slot of the link support 92 and then the link support is again carried forward with the pusher, moving upward along the face of the earn 104 into its operative position.

The operation of the horizontal feed unit of the feed mechanism is as follows. It is assumed that an ammunition belt is passing through the feed mechanism, that the leading cartridge of the belt is in position above the feeder mouth 16 with the pusher 18 engaging the rear face of the cartridge and the link support 92 engaging the link, and that two loose rounds are in the feeder mouth 16 which engages in the ammunition feedway of the gun, the nose of the lower round projecting toward the tube of the gun. Upon firing the gun, the lowermost round is picked up by the forward moving breech bolt. During recoil, the cam '66 moves with the recoiling gun parts and swings the levers 56, 34 in a clockwise direction (Fig. 3) about the axis of the shaft 36 by acting upon the cam roll 64. The pusher 18, carrying the support 92 with it, is consequently moved to the right, away from the feeder mouth, to a position in which it will assume control over another cartridge and the spring 38 is simultaneously energized; When the projection 74 of the hook 58 engages the release plate 76the hook is swung upward against the pressure of its plunger 62' out of engagement with the pin 61), thereby releasing the lever 34. The spring 38 now swings the lever 34 in a counterclockwise direction (Fig. 3) about the axis of the shaft 36, imparting feed movement to the pusher .18 and moving another cartridge into position above the feeder mouth 16. In moving toward the feeder mouth, the pusher returns the link support 92 to its operative position. At the end of the counter-recoil movement the cam lever 5'6 is released by the cam 66 and the hook 58 is moved from its disengaged position, shown in Fig. 1, into engagement with the pin 60 by the spring-pressed plunger 62 and the spring 82.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

In an ammunition feed mechanism adapted to be mounted on an automatic gun to feed cartridges from a linked belt to the ammunition feedway'of the gun, a

feeder mouth mounted'in the ammunition feedway, a pusher movable between a retracted position and the feeder mouth to bring successive cartridges into a position above the feeder mouth, a movable link support for engaging the link of the cartridge positioned above the feeder mouth, a slot in the link support, a fulcrum pin engaging in the slot and permitting longitudinal and swinging movements of the link support, a lost motion connection between the pusher and the link support for effecting movement of said support with the pusher, a cam for guiding the link support during movement with the pusher, and a spring for maintaining'the linkv support in engagement with the cam.

References Cited in the file of this patent UNITED STATES PATENTS 1,674,370 -Methlin June 19, 1928 1,808,847 Hatcher s June 9, 1931 2,047,596 Romberg July 14, 1936 2,101,086 Moore Dec. 7, 1937 2,388,670 Bixby' Nov. 13, 1945 2,397,501 :Meyer Apr..2, 1946 2,415,413 Burgess 'Feb. 11, 1947 2,453,977 Earnest; Nov. 16, 1948 

